Housing material of an exhaust gas treatment component

ABSTRACT

A housing of an exhaust gas treatment component is formed of a material having the following composition: iron: between 50 and 60 wt. %, nickel: between 16 and 24 wt. %, chromium: between 15 and 18 wt. %, aluminium: between 4 and 8 wt. %, and silicon: between 0.5 and 1.5 wt. %.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuing application, under 35 U.S.C. § 120, of copending international application No. PCT/EP2007/062326, filed Nov. 14, 2007, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. DE 10 2006 055 879.0, filed Nov. 24, 2006; the prior applications are herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a housing of an exhaust treatment component such as, for example, a catalytic converter, an adsorber, a filter, a particle trap. or the like, for use in an exhaust treatment installation, in particular such an installation in a motor vehicle.

At present, it is known for both ferritic and austenitic alloys to be used as a basis for such a housing. Housings of this type must, in particular, be suitable for having a predefined mechanical strength even up to temperatures of up to 800° C. and above, in order to ensure permanent fixing even when the exhaust treatment component is subjected to considerable dynamic loads.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a material for the housing of an exhaust gas treatment component which overcomes a variety of disadvantages of the heretofore-known devices of this general type and which provides a material composition for a housing of an exhaust treatment component that satisfies the requirements mentioned above.

With the foregoing and other objects in view there is provided, in accordance with the invention, a housing of an exhaust gas treatment component, comprising a material having the following composition:

-   -   iron: 50 to 60% by weight,     -   nickel: 16 to 24% by weight,     -   chromium: 15 to 18% by weight,     -   aluminum: 4 to 8% by weight,     -   silicon: 0.5 to 1.5% by weight.

The nickel/aluminum-containing austenitic steel disclosed here has a relatively high nickel content. This composition is particularly suitable for receiving metallic and brazed honeycomb bodies since these consist of a material similar to that of the brazed regions themselves, and an outstanding oxidation behavior is therefore achieved overall. This applies in particular when the metallic foils are joined together with a brazing material which results in a brazing region comprising approximately 70% nickel, 18% chromium and 10% silicon. Intermetallic nickel-aluminum precipitations, which greatly increase the mechanical strength properties at least up to temperatures of approximately 800° C., in particular compared with a simple austenitic steel material, occur precisely with the composition claimed, and the wall thickness of the converter shell can therefore be reduced. This possibility of reducing the wall thickness additionally makes it possible to provide housings of this type at lower cost and at lower weight, which are both very desirable.

Preference is given to a housing in which the composition mentioned above is varied with regard to at least one of the following constituents:

-   -   iron: 54 to 58% by weight,     -   nickel: 18 to 22% by weight,     -   chromium: 16 to 18% by weight,     -   aluminum: 5 to 7% by weight,     -   silicon: 0.8 to 1.2% by weight.         This means, in particular, that one or at least two of the         constituents mentioned is or are selected in the narrower range.

Particular preference is given to a housing in which the composition is varied with regard to at least one of the following constituents:

-   -   iron: 56% by weight,     -   nickel: 20% by weight,     -   chromium: 17% by weight,     -   aluminum: 6% by weight,     -   silicon: 1% by weight,         wherein a tolerance range of 5% is permissible with regard to at         least one constituent. This means, in particular, that the         tolerance range can vary upward and/or downward about the stated         value. The tolerance range is preferably at most 2% or even at         most 0.5%.

Preference is given to using the housing with a thickness of less than 1 mm (millimeter), in particular less than 0.8 mm. In this case, the housing is used, in particular, for receiving a metallic honeycomb body which is brazed to the housing at high temperature. For this purpose, the honeycomb body may be constructed with at least partially structured metallic foils, such that passages, through which the exhaust gas can flow, are formed. All the foils are preferably brazed (at both ends) to the housing on the circumferential side.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a component for an exhaust gas treatment system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of the specific embodiment when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

The sole FIGURE is a perspective view of a component of an exhaust gas treatment system.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring now to the figure of the drawing in detail, there is shown an exhaust treatment component 6 comprising a housing 1 and a honeycomb body 5, which is positioned in the interior 4 of the housing 1. The honeycomb body 5 is designed with a plurality of corrugated and smooth metal foils 7 which are stacked and wound together such as to form passages 8 through which the exhaust gas can flow. An exhaust treatment component 6 of this type may be designed, in particular, as a catalyst support, a mixing element, an adsorber, a particle trap, or the like. In this case, the housing 1, illustrated here with a cylindrical shape, has a length 3 and a thickness 2. The thickness 2 is advantageously in a range of less than 1 mm. In particular, it is less than 0.8 mm. 

1. A housing of an exhaust gas treatment component, comprising a material having the following composition: iron: 50 to 60% by weight, nickel: 16 to 24% by weight, chromium: 15 to 18% by weight, aluminum: 4 to 8% by weight, silicon: 0.5 to 1.5% by weight.
 2. The housing according to claim 1, wherein the composition is varied with regard to at least one of the following constituents: iron: 56 to 58% by weight, nickel: 18 to 22% by weight, chromium: 16 to 18% by weight, aluminum: 5 to 7% by weight, silicon: 0.8 to 1.2% by weight.
 3. The housing according to claim 1, wherein the composition is varied with regard to at least one of the following constituents: iron: 56% by weight, nickel: 20% by weight, chromium: 17% by weight, aluminum: 6% by weight, silicon: 1% by weight, and wherein a tolerance range of 5% is permissible with regard to at least one constituent.
 4. The housing according to claim 1, wherein said housing has a wall thickness of less than 1 mm.
 5. The housing according to claim 1, wherein said housing has a wall thickness of less than 0.8 mm.
 6. A housing of an exhaust gas treatment component, comprising a material consisting of the following composition: iron: 50 to 60% by weight, nickel: 16 to 24% by weight, chromium: 15 to 18% by weight, aluminum: 4 to 8% by weight, silicon: 0.5 to 1.5% by weight.
 7. The housing according to claim 6, wherein the composition consists of the following constituents: iron: 56 to 58% by weight, nickel: 18 to 22% by weight, chromium: 16 to 18% by weight, aluminum: 5 to 7% by weight, silicon: 0.8 to 1.2% by weight.
 8. The housing according to claim 7, wherein the composition consists of the following constituents: iron: 56% by weight, nickel: 20% by weight, chromium: 17% by weight, aluminum: 6% by weight, silicon: 1% by weight, and a tolerance range of 5% by weight is permissible with regard to at least one constituent. 